海康USB摄像头----MV-CAO13-21UM工业摄像头的调用---python实现

图像采集

主动取流流程

回调出流流程图

手册上是通过C语言实现的：

海康调用C语言的动态链接库实现的python库

这些库文件在海康威视的MVS软件安装包里面，找一找就能找到。

本次实现了主动取流

1. 通过MV_CC_EnumDevices(MV_USB_DEVICE, device_list)搜索存在的USB设备。

2. 获取设备信息cast(device_list.pDeviceInfo[int(show_device_num)], POINTER(MV_CC_DEVICE_INFO)).contents

3. 创建句柄cam = MvCamera()

4. 获得设备的句柄cam.MV_CC_CreateHandle(device_info)

5. 打开设备cam.MV_CC_OpenDevice(MV_ACCESS_Exclusive, 0)

6. 获得设备的参数存在MVCC_INTVALUE()这个结构里面，cam.MV_CC_GetIntValue(“PayloadSize”, camera_int_param)

7. 获取图片的存储大小，还有长度

   image_data_size = (c_ubyte * camera_int_param.nCurValue)()image_data_length = camera_int_param.nCurValue
   

8. 开始抓流

   grab_ret = cam.MV_CC_StartGrabbing()
   

9. 图片信息存在下面的结构中

   frame_info = MV_FRAME_OUT_INFO_EX()
   memset(byref(frame_info), 0, sizeof(frame_info))
   

10. 获取流

    cam.MV_CC_GetOneFrameTimeout(image_data_size, image_data_length, frame_info, 1000)
    

11. 将图片格式转一转

    			   nRGBSize = frame_info.nWidth * frame_info.nHeight
                    convert_param = MV_CC_PIXEL_CONVERT_PARAM()
                    memset(byref(convert_param), 0, sizeof(convert_param))
                    convert_param.nWidth = frame_info.nWidth
                    convert_param.nHeight = frame_info.nHeight
                    convert_param.pSrcData = image_data_size
                    convert_param.nSrcDataLen = frame_info.nFrameLen
                    convert_param.enSrcPixelType = frame_info.enPixelType
                    convert_param.enDstPixelType = frame_info.enPixelType
                    convert_param.pDstBuffer = (c_ubyte * nRGBSize)()
                    convert_param.nDstBufferSize = nRGBSize
                    ret = cam.MV_CC_ConvertPixelType(convert_param)
    

12. img_buff = (c_ubyte * convert_param.nDstLen)()
    cdll.msvcrt.memcpy(byref(img_buff), convert_param.pDstBuffer, convert_param.nDstLen)
    img = np.array(img_buff, dtype=np.int8)
    Img = img.reshape(1024, 1280)
    Img = cv.flip(Img, -1)
    Img = cv.flip(Img, -1)
    

13. 整体代码如下：

# _*_coding:UTF-8_*_
# 当前系统用户: LISICHENG   
# 当前系统日期：2019/7/29   
# 当前系统时间：13:55   
# 创建文件的IDE名称：PyCharm
import cv2 as cv
import numpy as np
from MvImport.CameraParams_const import *
from MvImport.CameraParams_header import *
from MvImport.MvCameraControl_header import *
from MvImport.MvCameraControl_class import *
from MvImport.MvErrorDefine_const import *
from MvImport.PixelType_const import *
from MvImport.PixelType_header import *

class AccessToImages():

    def FindDevices(self):
        device_list = MV_CC_DEVICE_INFO_LIST()
        find_device_ret = MvCamera.MV_CC_EnumDevices(MV_USB_DEVICE, device_list)
        if find_device_ret == 0:
            return device_list
        else:
            return False

    def GetImages(self, show_device_num, device_list):
        i = 0
        if show_device_num <= device_list.nDeviceNum:
            device_info = cast(device_list.pDeviceInfo[int(show_device_num)], POINTER(MV_CC_DEVICE_INFO)).contents
            cam = MvCamera()
            handle_ret = cam.MV_CC_CreateHandle(device_info)
            if handle_ret != 0:
                print("创建句柄失败")
            # 打开设备
            open_device = cam.MV_CC_OpenDevice(MV_ACCESS_Exclusive, 0)
            if open_device != 0:
                print('开启失败')

            # 获取相机int型节点值  "PayloadSize" 为当前节点得名称,一帧节点的大小
            camera_int_param = MVCC_INTVALUE()
            int_value_ret = cam.MV_CC_GetIntValue("PayloadSize", camera_int_param)
            if int_value_ret != 0:
                print('获取图像信息失败')
            image_data_size = (c_ubyte * camera_int_param.nCurValue)()
            image_data_length = camera_int_param.nCurValue
            # 开始抓流
            grab_ret = cam.MV_CC_StartGrabbing()
            if grab_ret != 0:
                print('抓起流失败')
            # 获取数据大小

            # 下面将获得每一帧的图像
            while True:
                frame_info = MV_FRAME_OUT_INFO_EX()
                memset(byref(frame_info), 0, sizeof(frame_info))

                frame_ret = cam.MV_CC_GetOneFrameTimeout(image_data_size, image_data_length, frame_info, 1000)
                if frame_ret != 0:
                    print('获取帧信息失败')

                nRGBSize = frame_info.nWidth * frame_info.nHeight
                convert_param = MV_CC_PIXEL_CONVERT_PARAM()
                memset(byref(convert_param), 0, sizeof(convert_param))
                convert_param.nWidth = frame_info.nWidth
                convert_param.nHeight = frame_info.nHeight
                convert_param.pSrcData = image_data_size
                convert_param.nSrcDataLen = frame_info.nFrameLen
                convert_param.enSrcPixelType = frame_info.enPixelType
                convert_param.enDstPixelType = frame_info.enPixelType
                convert_param.pDstBuffer = (c_ubyte * nRGBSize)()
                convert_param.nDstBufferSize = nRGBSize
                ret = cam.MV_CC_ConvertPixelType(convert_param)
                if ret != 0:
                    print("convert pixel fail! ret[0x%x]" % ret)
                    del image_data_size
                    sys.exit()
                img_buff = (c_ubyte * convert_param.nDstLen)()
                cdll.msvcrt.memcpy(byref(img_buff), convert_param.pDstBuffer, convert_param.nDstLen)
                img = np.array(img_buff, dtype=np.int8)
                Img = img.reshape(1024, 1280)
                Img = cv.flip(Img, -1)
                Img = cv.flip(Img, -1)
                cv.imshow('img' + str(show_device_num), Img)
                cv.waitKey(25)


if __name__ == '__main__':

    a = AccessToImages()
    device_list = a.FindDevices()
    if a:
        a.GetImages(0, device_list)
    # print(device_list.nDeviceNum)

运行时有问题的，操作系统是windows，海康工业相机 USB相机，需要源代码的，下面留下邮箱哈，我发给您；